title: The creation and annihilation of optical vortices using cascade conical diffraction.
abstract: Internal conical diffraction produces a superposition of orthogonally polarised zero- and first-order Bessel like beams from an incident circularly polarised Gaussian beam. For right-circularly polarised light, the first-order beam has an optical vortex of charge -1. Upon propagation of the first-order beam through a second biaxial crystal, a process which is termed cascade conical refraction, the generated beam is a superposition of orthogonally polarised fields of charge 0 and -1 or 0 and -2. This spin to orbital angular momentum conversion provides a new method for the generation and annihilation of optical vortices in an all-optical arrangement that is solely dependent on the incident polarisation and vortex handedness.
authors.affiliation: School of Physics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: D P
authors.initials: DP
authors.lastname: O'Dwyer
authors.forename: C F
authors.initials: CF
authors.lastname: Phelan
authors.forename: Y P
authors.initials: YP
authors.lastname: Rakovich
authors.forename: P R
authors.initials: PR
authors.lastname: Eastham
authors.forename: J G
authors.initials: JG
authors.lastname: Lunney
authors.forename: J F
authors.initials: JF
authors.lastname: Donegan
mesh_terms: D003198:Computer Simulation; D008027:Light; D015233:Models, Statistical; D017711:Nonlinear Dynamics; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation